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Completed

NCT Number: NCT05444517

Interscalene Block Versus Combined Infraclavicular-Anterior Suprascapular Blocks for Shoulder Surgery

Postoperative analgesia after shoulder surgery remains a challenge in patients with preexisting pulmonary pathology, as interscalene brachial plexus block (ISB), the standard nerve block for shoulder surgery, carries a prohibitive risk of hemidiaphragmatic paralysis (HDP). Although several diaphragm-sparing nerve blocks have been proposed, none seems to offer equivalent analgesia to ISB while avoiding HDP altogether. For instance, even costoclavicular blocks, which initially fulfilled both requirements, were subsequently found to result in a non-negligible 5%-incidence of HDP.

In this randomized trial, the authors set out to compare ISB and combined infraclavicular block-anterior suprascapular nerve blocks (ICB-ASSNB) for patients undergoing arthroscopic shoulder surgery. The authors hypothesized that ICB-ASSNB would provide equivalent postoperative analgesia to ISB 30 minutes after shoulder surgery and therefore designed the current study as an equivalence trial.

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Key information

Conditions

Pain, Postoperative Arthralgia Diaphragmatic Paralysis Joint Diseases Musculoskeletal Diseases Nervous System Diseases Neurologic Manifestations Pain Paralysis Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Respiration Disorders Respiratory Insufficiency Respiratory Paralysis Respiratory Tract Diseases Shoulder Pain Signs and Symptoms Surgical Procedure, Unspecified

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Hospital Clínico Universidad de Chile

Santiago, Santiago Metropolitan, Chile

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients undergoing arthroscopic shoulder surgery
  • American Society of Anesthesiologists classification 1-3
  • Body mass index between 20 and 35 kg/mt2

Exclusion criteria

  • Adults who are unable to give their own consent
  • Pre-existing neuropathy (assessed by history and physical examination)
  • Coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. platelets ≤ 100, International Normalized Ratio ≥ 1.4 or prothrombin time ≥ 50)
  • Obstructive or restrictive pulmonary disease (assessed by history and physical examination)
  • Renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. creatinine ≥ 100)
  • Hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. transaminases ≥ 100)
  • Allergy to local anesthetics (LAs)
  • Pregnancy
  • Prior surgery in the neck or infraclavicular region
  • Chronic pain syndromes requiring opioid intake at home

Treatment and study plan

interscalene block

Procedure

Ultrasound-guided brachial plexus block injecting 20 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml in the Interscalene groove.

Patients will receive dexamethasone 4 mg intravenously and an ultrasound-guided intermediate cervical plexus block (5 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml).

Other names: Peripheral Nerve Block

Infraclavicular - Anterior Supraescapular Nerve Blocks

Procedure

Ultrasound-guided combined infraclavicular-anterior suprascapular block of the brachial plexus, injecting 20 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml dorsal to the axillary artery in the infraclavicular fossa plus an ultrasound-guided injection of 3 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml under the omohyoid muscle. If the anterior suprascapular nerve could not be identified after five minutes of insonation time, an upper trunk block will be carried out with the same amount of local anesthetic.

Patients will receive dexamethasone 4 mg intravenously and an ultrasound-guided intermediate cervical plexus block (5 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml).

Other names: Peripheral Nerve Block

Primary outcomes

  1. Static pain 30 minutes after arrival in the post anesthesia care unit (PACU)

    Time frame: 30 minutes after PACU arrival

    Pain intensity at rest using a numeric rating score (NRS) ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

Secondary outcomes

  1. Static pain 1 hour after arrival in the PACU

    Time frame: 1 hour after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  2. Static pain 3 hours after arrival in the PACU

    Time frame: 3 hours after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  3. Static pain 6 hours after arrival in the PACU

    Time frame: 6 hours after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  4. Static pain 12 hours after arrival in the PACU

    Time frame: 12 hours after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  5. Static pain 24 hours after arrival in the PACU

    Time frame: 24 hours after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  6. Static pain 36 hours after arrival in the PACU

    Time frame: 36 hours after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  7. Static pain 48 hours after arrival in the PACU

    Time frame: 48 hours after PACU arrival

    Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)

  8. Block performance time

    Time frame: 1 hour before surgery

    Time from skin disinfection until the end of local anesthetic injection

  9. Intensity of pain during block procedure

    Time frame: 1 hour before surgery

    Evaluated with the Numeric Rating Scale for Pain. This scale is graduated from 0 to 10 points. A 0-point score represents the absence of pain, and a 10-points score represents the worst imaginable pain. Patients will be asked to rate their pain verbally with this scale. The blinded assessor will register the score reported.

  10. Incidence of nerve block side effects

    Time frame: 0 minutes after skin disinfection to 30 minutes after the nerve block

    Determined by the presence of paresthesia, local anesthetic systemic toxicity, vascular puncture, Horner syndrome, or hoarseness after the block.

  11. Sensory and motor block score

    Time frame: 30 minutes after the ending time of local anesthetic injection

    The sensorimotor block will be assessed every 5 minutes until 30 minutes after the end of local anesthetic injection using a 14-point composite score that encompasses the sensory functions of the axillary and supraclavicular nerves as well as the motor functions of the axillary, suprascapular, subscapular and lateral pectoral nerves

    Sensation will be assessed with ice in each nerve territory with a 0 to 2 point scale. 0= no block, patients can feel cold; 1= analgesic block, the patient can feel touch but not cold; 2= anesthetic block, the patient cannot feel cold or touch.

    The motor function will be assessed for each nerve with a 0 to 2 points scale where 0= no motor block; 1= paresis; 2= paralysis.

    Successful blocks at 30 minutes correlate with a final score ( sum of all individual sensory and motor scores) of at least 12 points out of 14, with a sensory score of at least 3 points (out of 4 points).

  12. Block onset time

    Time frame: 1 hour before surgery

    Time required to reach a minimal sensorimotor composite score of 12 points out of a maximum of 14 points. The sensorimotor score is described in outcome 12.

  13. Basal diaphragmatic function

    Time frame: 1 hour before surgery

    Diaphragmatic function evaluated before the nerve block

  14. Incidence of hemidiaphragmatic paralysis (HDP) at 30 minutes after interscalene or infraclavicular-suprascapular block

    Time frame: 30 minutes after the ending time of local anesthetic injection

    HDP will be defined as the absence of diaphragmatic motion during normal respiration coupled with absent or (paradoxical) cranial diaphragmatic movement when the patient forcefully sniffs

  15. Incidence of HDP 30 minutes after PACU arrival

    Time frame: 30 minutes after PACU arrival

    HDP will be defined as the absence of diaphragmatic motion during normal respiration coupled with absent or (paradoxical) cranial diaphragmatic movement when the patient forcefully sniffs

  16. Duration of surgery

    Time frame: 4 hours after skin incision

    Time between skin incision and closure (min)

  17. Postoperative opioid related side effects

    Time frame: 48 hours after PACU arrival

    Presence of postoperative nausea, vomiting, pruritus, urinary retention, respiratory depression.

  18. Intraoperative opioid requirements

    Time frame: Intraoperative period

    Total amount of fentanyl required during general anesthesia

  19. Postoperative opioid consumption

    Time frame: 48 hours after PACU arrival

    Total amount of morphine required during the first 48 hours after surgery

  20. Patient satisfaction

    Time frame: 24 hours after PACU arrival

    Patient satisfaction at 24 hours using a 0-10 scale (0 = not satisfied; 10 = very satisfied)

  21. Persistent neurologic deficit

    Time frame: 7 days after surgery

    Presence of persistent sensory or motor postoperative deficit. The patients will be contacted by telephone and inquired about any sensory or motor deficit in the operated extremity.

Sponsors and collaborators

Lead sponsor

University of Chile

Other

Registry information

Official study title

A Randomized Comparison Between Interscalene And Combined Infraclavicular-Anterior Suprascapular Nerve Blocks For Arthroscopic Shoulder Surgery

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Jul 6, 2022
Registry last updated
Dec 29, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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